closest point python code example

Example: closest point python

#kd-tree for quick nearest-neighbor lookup
import geopandas as gpd
import numpy as np
import pandas as pd

from scipy.spatial import cKDTree
from shapely.geometry import Point

gpd1 = gpd.GeoDataFrame([['John', 1, Point(1, 1)], ['Smith', 1, Point(2, 2)],
                         ['Soap', 1, Point(0, 2)]],
                        columns=['Name', 'ID', 'geometry'])
gpd2 = gpd.GeoDataFrame([['Work', Point(0, 1.1)], ['Shops', Point(2.5, 2)],
                         ['Home', Point(1, 1.1)]],
                        columns=['Place', 'geometry'])

def ckdnearest(gdA, gdB):
    nA = np.array(list(gdA.geometry.apply(lambda x: (x.x, x.y))))
    nB = np.array(list(gdB.geometry.apply(lambda x: (x.x, x.y))))
    btree = cKDTree(nB)
    dist, idx = btree.query(nA, k=1)
    gdf = pd.concat(
        [gdA.reset_index(drop=True), gdB.loc[idx, gdB.columns != 'geometry'].reset_index(drop=True),
         pd.Series(dist, name='dist')], axis=1)
    return gdf

ckdnearest(gpd1, gpd2)